EP0037540B1 - Verfahren und Schaltungsanordnung zur Zuführung von Rufsignalen zu Fernmeldeleitungen, insbesondere in Fernsprechvermittlungsanlagen - Google Patents

Verfahren und Schaltungsanordnung zur Zuführung von Rufsignalen zu Fernmeldeleitungen, insbesondere in Fernsprechvermittlungsanlagen Download PDF

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Publication number
EP0037540B1
EP0037540B1 EP81102363A EP81102363A EP0037540B1 EP 0037540 B1 EP0037540 B1 EP 0037540B1 EP 81102363 A EP81102363 A EP 81102363A EP 81102363 A EP81102363 A EP 81102363A EP 0037540 B1 EP0037540 B1 EP 0037540B1
Authority
EP
European Patent Office
Prior art keywords
ringing
circuit
signal bus
call
circuits
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP81102363A
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German (de)
English (en)
French (fr)
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EP0037540A2 (de
EP0037540A3 (en
Inventor
Santanu Das
Ramon C.W. Chea, Jr.
Russ C. Casterline
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Alcatel Lucent NV
Original Assignee
International Standard Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
Priority to AT81102363T priority Critical patent/ATE17294T1/de
Publication of EP0037540A2 publication Critical patent/EP0037540A2/de
Publication of EP0037540A3 publication Critical patent/EP0037540A3/de
Application granted granted Critical
Publication of EP0037540B1 publication Critical patent/EP0037540B1/de
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M19/00—Current supply arrangements for telephone systems
    • H04M19/02—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone
    • H04M19/023—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone by reversing the polarity of the current at the exchange

Definitions

  • the invention relates to a method of the type specified in the preamble of claim 1 and a circuit arrangement for carrying out the method.
  • the call signals are usually delivered in such a way that only one subscriber line to be called can be supplied with call signals at the same time from a call circuit. Therefore, in addition to the call circuit which generates the call stream, a call answering detector must be provided which, after the called subscriber has reported, causes the call signals to be switched off from this subscriber line and which therefore makes it possible to connect the same call circuit in succession to many subscriber lines to be called.
  • a call signal usually consists of a short phase call stream with a subsequent, longer call pause, and is repeated cyclically in the so-called call cycle.
  • each call must be equipped with two call signal generators.
  • One call signal generator has to work constantly, while the other works in phases.
  • Such a call circuit has a controller that connects the subscriber line to be called for a certain period of time, for example 300 ms, to the continuously operating call signal generator and then to the call signal generator working in phases.
  • These known ringing circuits require either different or such ringing current sources for multi-frequency ringing signals or for ringing signals of different frequencies that can provide any type of ringing current.
  • the different call signals have to be transmitted via trunk groups, or several relays or switches have to be used for each call circuit.
  • U.S. Patent No. 3,005,053 is concerned with a telephone signaling system that transmits different signal frequencies in different time slots.
  • US Pat. No. 3,085,133 relates to an automatically controlled call signal supply, the call stream being made available immediately after the connection has been switched through, but thereafter in accordance with the usual call cycle.
  • U.S. Patent 3,118,018 relates to connecting a paging power source to a desired telephone set via a pair of gates connected in series, both of which must operate in phase for the paging current to reach the telephone set.
  • Subscriber circuits of the type that can be used in connection with the present invention and that include programmable signal generators that can generate AC and DC signal voltages have been described, for example, in U.S. Patent 4,161,633. Details of the programmable signal generation in a digital subscriber line circuit are also given there.
  • Digital telephone switching networks of a type in which the present invention can be used particularly advantageously have been proposed in detail in DE-OS 29 09 762.
  • US Pat. No. 4,097,694 describes a computer-controlled intercom with time division operation, in which the call is also routed via gates provided for time division operation.
  • There are several generators for the call presumably working on the same frequency, which can be switched through to the called subscribers via assigned gates.
  • the type and control of the call generators are not exactly described.
  • the generators are assigned to different cycle types. According to various combinations of certain bits in a logic circuit, for example, the ringing tone and the ringing tone can be controlled; the generators are also intended for audible tones.
  • This known intercom system is digitally controlled, but the speech signals themselves are not transmitted in coded form.
  • the ringing alternating voltages are fed directly to a ringing signal bus.
  • the intercom works with a pause detector.
  • the technical object of the method according to the invention is to supply the telecommunication lines with the necessary call signals, the method fulfilling special conditions, such as, for. B. Call with different call signal frequencies, different call signal cadences and multi-frequency call signals.
  • a special design of the process according to the invention is characterized in claim 2.
  • the demands for different call signal cadences and for an immediate call can be met particularly easily, namely in a uniform manner.
  • the technical object of the circuit arrangement according to the invention is to supply the necessary call signals to telecommunication lines as required. It is said to be particularly suitable for carrying out the method according to claim 1 in digitally operating telephone switching systems in which central feed-in of call signals is not suitable because of the digital connection in the switching network, usually via semiconductor coupling points.
  • the circuit arrangement according to the invention should also be usable in general, with slightly different call methods on telecommunication lines.
  • connection device 10 which comprises a group of 60 subscriber connection circuits and which is connected to a digital switching network via an adaptation circuit 12.
  • the connection device 10 forms a connection module which comprises a programmable power supply for adapting analogue subscriber lines and connecting lines to a digitally operating telephone exchange with all analogue-digital conversions, digitai-analogue conversions and two-wire-four-wire transitions.
  • connection device 10 also includes connection elements for connecting the call signals and other audio frequency voltages for measurement, testing and line monitoring. Continuous monitoring under control with a wired program or under control with a microprocessor for a programmable signal generator is also used to detect potential changes on the wires of the subscriber lines.
  • the filtering out of voice signals can be achieved under the control of a microprocessor or hard-wired program.
  • Such a subscriber line circuit has been described in U.S. Patent 4,161,633.
  • the digital switching network can work with a distributed control.
  • the voice signals are PCM coded in time-division multiplexed transmission over lines 16 and 18, each of which has 32 channels, so that no blocking occurs when accessing the matching circuit 12 for the 60 connected lines.
  • Another pair of lines 20, 22 each with 32 channels leads from the matching circuit 12 to the switching network; these lines are also operated using time division multiplexing.
  • the connection device 10 is connected to the microprocessor 24 via a data bus 28; The data is transmitted at a low speed on this data bus.
  • the adaptation circuit 12 is also connected to the microprocessor 24 via a further data bus 30; The data is transmitted at high speed on this data bus.
  • the data bus 28 is used by the microprocessor 24, for example, to control analog subscriber lines or other connected devices; the microprocessor 24 is preferably of the Intel 8086 type. B. consist of thirteen wires over which addresses and data are transmitted in multiples.
  • the function of the adaptation circuit 12 and associated peripheral devices operating at high speed is controlled via the data bus 30.
  • the data bus 30 includes a control path between the microprocessor 24 and a memory 26. Microprocessor 24 and memory 26 form a microcomputer.
  • the data bus 30 includes separate wires for addressing and data transmission, the data wires allowing the transmission of 16-bit words.
  • Fig. 2 shows a block diagram of details of a connection device 10, which is set up to connect 60 subscriber lines. It takes care of the line termination functions, the call functions, other common line functions, adaptation functions and for access to the microcomputer 33.
  • the connection device 10 which for example has a block 31 with sixty subscriber line circuits, forms a security block of line connections. Eight such connection devices (10) form a connection unit (480 subscriber line below). One connection device (10) per connection unit is reserved as a replacement unit in the event that one of the other connection devices is working incorrectly.
  • Each connection device 10 has a call circuit block 32 with two call circuits, each of which serves 30 subscriber lines.
  • a multiplexer 34 for the common transmission of digitized analog control signals and test circuits 36 are provided to provide access for testing all subscriber lines.
  • FIG. 3 the structure of the analog connection devices (10) of a connection unit is shown.
  • Each connection unit comprises eight connection devices (10) No. 0 to 7, of which only No. 0 and No. 7 are shown here.
  • 60 subscriber lines with their speech wires are connected to the connection device (10) No. 0.
  • the four subscriber lines 42, 44, 46 and 48 are shown.
  • extended connection circuits 50, 52, 54 and 56 two relays each ensure an independent and individual connection with two test signal buses 58 and 60, which are also indicated in FIG. 2.
  • the subscriber line 42 of the connection device No. 0 is connected to the outer test signal bus 58 via the relays 62 and 64 and to the inner test signal bus 60 via the relays 66 and 68.
  • a metallic connection to the test signal buses 58 and 60 for the subscriber lines 46 and 48 in the connection device No. 0 and for the subscriber lines in the connection devices No. 1 to 7 is possible via corresponding relays.
  • the operation of the relays 62 to 68 divides the subscriber line loop 42 into two parts, the outer part of the subscriber line being completely separated from the inner part of the line loop when each wire of the subscriber line 42 is connected to the test signal buses 58 and 60.
  • test connection element 70 which is typically in telephone exchanges a device which also takes on additional functions in addition to the test functions, the test signal buses for troubleshooting and for the search for faulty line sections, such as in the event of a line short , to be used.
  • the test connection element 70 also includes a circuit which, in the event of a connection circuit malfunction, causes a replacement connection circuit to be provided until the faulty connection circuit is ready for operation again. This replacement is particularly important in unmanned switching systems.
  • Each call circuit of the call circuits 74, 76, 78 is provided for 30 subscriber lines, each of which can be connected to the relevant call circuit via a call signal bus 82 if a call relay 84 in the extended connection circuit 52 is controlled accordingly.
  • the call circuit 74 and the call relay 84 are controlled by the microcomputer 33.
  • the program in the microcomputer also determines the call signal sequence and the individual call signal, the pulse / pause ratio, the frequency and the DC bias.
  • the call circuit 74 also has an arrangement for monitoring the line loop, which detects the lifting of the handset and then shuts off the call and which checks the continuation of the line loop on the calling party side during the calling process.
  • connection circuit within the group of 480 connection circuits is used as an equivalent connection circuit.
  • the size of the group is variable depending on the system requirements. If a connection circuit malfunctions, which is recognized by the maintenance program within the microcomputer or by other detection circuits, for example in the test connection element 70, the replacement connection circuit is switched on to the subscriber line concerned instead of the faulty connection circuit. In this way, operation is maintained until the routine maintenance service clears the fault.
  • the call relays 84 are switched load-free, i. that is, the contacts of the call relay are opened or closed when no current flows through these contacts.
  • the call relay contacts are opened or closed regardless of whether current flows through the contacts or not. Therefore, large and therefore more expensive contacts are common, which can withstand the arc that arises when the relay is switched off.
  • the subscriber line loop also represents a large inductance, so that an interruption in the current results in a high voltage peak. This leads to sparking on a printed circuit board, which acts as an interference voltage in neighboring circuits.
  • a suitable control signal is generated within a control circuit 118 with the aid of a microcomputer connected to this control circuit, so that the call relay 84 only then switched when no current flows through its contacts.
  • FIG. 4 shows a call circuit 74 for generating a call signal.
  • Two such call signal generation circuits together with the call relays of the extended connection circuits and the programmed control in the microcomputer form a call unit.
  • the programming chosen is not the subject of the invention.
  • the call features mentioned here, such as call duration etc. are variable with the aid of control signals from any such microcomputer or a programmably controlled input of the call circuit.
  • FIG. 4 the call circuit 74 is a little more detailed for a better understanding, although such a call circuit is the subject of a parallel application (EP-A-0037111, priority 31.3.80 filing date March 28, 1981).
  • a programmable call signal generator 110, 112 generates a call signal under the control of the microcomputer, as has been described in the already mentioned US Pat. No. 4161633.
  • the generated call signal is fed from the output stage 112 of the programmable call signal generator via the call signal bus 82 to the speech wires T, R.
  • Call reference signals from call signal reference voltage sources reach an analog multiplexer 114 and then ultimately to the output stage 112 of the call signal generator.
  • Square waves which are synchronized with the call reference signals, are also fed to the output stage 112 of the call signal generator, specifically via a switching amplifier 116, which is also controlled by a logic signal from the control circuit 118.
  • a call pause detector 124 and a call answering detector 122 are provided to supply the control circuit 118 with information about the call signals on the call signal bus 82.
  • a twelve-wire control connection from the microprocessor leads to a pair of paging circuits 74, 76 which each feed 30 lines over a common paging bus.
  • a number of low level signals of various frequencies f1 through f4 that are generated in call signal reference voltage sources 100, 102, 104 and 106 are provided to call circuits 74 and 76. These call circuits operate as power amplifiers that bring the low voltage signals to high voltage signals.
  • the low level signals are sine waves (outputs S) or square waves (outputs R) of the call signal reference voltage sources 100 to 106.
  • the signals coming from the call circuits 74, 76 are power signals required for calling via the subscriber lines.
  • the call relays in the connection circuits are excited and de-energized synchronously with the call circuit so that call signals of a desired cadence and frequency can be fed in and thus a load-free switching operation of the call relays can be achieved in the connection circuits.
  • the call signal can either be fed between one of the speech wires and earth or via both speech wires.
  • the call circuit 74 or 76 detects the lifting of the handset during a call interval in the call cycle and switches off the call signal after a certain period of time (switch-off delay).
  • a call answering detector detects the direct current flow in the subscriber line.
  • a signal characterizing the off-hook condition of the handset is then transmitted to the control of the switching system.
  • FIG. 6 shows curves which indicate the distribution of the call phases.
  • four different phases are provided for up to four telephones with bridged alarm clocks that can be tuned to the frequencies of 20, 30, 40 and 50 Hz.
  • a call circuit operates fifteen lines, has four call phases and has a call signal with a 1.3 s ringing current pulse and a 4.7 s ringing pause, the following analysis can be carried out taking into account FIG. 6. Since each call circuit serves fifteen lines, there are four call phases for fifteen lines. If an incoming traffic of 0.05 Erlang / line, a connection hold time of 100 s and a call duration of 20 s are assumed, then the call traffic during the rush hour is 0.15 Erlang. With four call phases the blocking probability is less than 0.001.
  • a rush hour call traffic of 0.15 Erlang corresponds to a probability of 0.15 in the rush hour that at least one call phase is busy, ie the probability is 0.85 that no call phase is busy. Therefore, the immediate call probability is 0.85. This means that 85% of connection requests are immediately called. If traffic outside the rush hour is assumed to be one third of the traffic in the rush hour, the calculation of the immediate call probability gives the value 0.95. This means that 95% of the connection requests receive an immediate call. Taking Fig. 6b into account, it has been found that even under the heaviest call traffic condition, the probability that a line of 15 lines will be called is approximately 0.225. This means that 22.5% of the incoming connections find only one call phase occupied.
  • a probability of 0.78 can be calculated for the incoming connections to arrive in the period between points b and d (FIG. 6b) and thus an immediate call can be received, namely a call from phases 02 to 04 if phase 01 is busy.
  • the answering detector detects the lifting of a handset during the period c-b, then the call signal is switched off from the line. After the call has been switched off, the detectors of both subscriber lines which detect the lifting of the handset are monitored, and the line which is in the state which indicates that the handset is off-hook, is removed from a call list. From then on, the other line is finally given the same call phase. If there is no answering state during the time period c-b, the second line is assigned a free phase in the next call cycle and the first line to be called remains in its previous call phase. If the time period c-b is less than 300 ms and if there is no call answering state in this time period, then the second line can be disconnected from the call bus after 300 ms. From Fig. 6c it can be seen that the maximum call delay is approximately 300 ms after the dialing has taken place.
  • a further training has the purpose to guarantee practically no blocking at all and always an immediate call in the following way: If the time period b-c is less than or equal to 100 ms in FIG. In this way, the immediate call delay can be limited to 100 ms. If the time period b-c is greater than or equal to 100 ms, the first call pulse begins in one call phase and continues in the other call phase. This can easily be carried out in that the call relay of the subscriber line remains switched on, but that the call relay in the call circuit is switched off. Since the next call phase could already be occupied by another line before the call relay is switched on again, the line relay for the other line must also be energized.
  • a blocking due to missing call phases can be prevented by assigning several lines to the same call phase; in the case of a call answering, all lines assigned to the same call phase are then disconnected from the call circuit, and then the detectors which detect the lifting of the handset are queried, which line actually reports the state which indicates the lifting of the handset. The line having this state is then removed from the call list for this call phase, while the other lines are put back into the list and this call phase is switched through again.
  • FIG. 7 shows an embodiment of the answering detector 122 shown in FIG. 4, which can be used advantageously in the invention.
  • the subscriber loop is formed from a battery 200, a call generator 202, supply resistors 204, 206 (or equivalent circuits) and a loop impedance ZL. Resistor 206 is required for measuring the ringing current flowing in the subscriber loop.
  • An operational amplifier 208 with its bias resistors 210, 212, 214, 216, 218 and 220 works as an isolation amplifier, which enables the ringing and direct current signal appearing at resistor 206 to be further processed.
  • the call signal for example with a peak voltage of 200 V, is superimposed on the direct current signal in the usual way.
  • An operational amplifier 222 downstream of the operational amplifier 208 and its bias resistors 224, 228, 230 and capacitors 232, 234 form a low-pass filter which filters out the ring signal frequency and only the direct current signal reinforced.
  • An amplifier 236 connected downstream of the low-pass filter is designed as a comparator which compares the direct current output signal of the operational amplifier 222 with a reference voltage Vr.
  • the output of amplifier 236 is a loop condition signal which indicates either the on-hook handset line condition or the off-hook handset condition and is used to control the ringing and other parts of the switch with respect to the detected loop condition.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Devices For Supply Of Signal Current (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Telephone Function (AREA)
  • Optical Communication System (AREA)
  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
  • Telephonic Communication Services (AREA)
  • Reduction Or Emphasis Of Bandwidth Of Signals (AREA)
  • Use Of Switch Circuits For Exchanges And Methods Of Control Of Multiplex Exchanges (AREA)
  • Mobile Radio Communication Systems (AREA)
EP81102363A 1980-03-31 1981-03-28 Verfahren und Schaltungsanordnung zur Zuführung von Rufsignalen zu Fernmeldeleitungen, insbesondere in Fernsprechvermittlungsanlagen Expired EP0037540B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81102363T ATE17294T1 (de) 1980-03-31 1981-03-28 Verfahren und schaltungsanordnung zur zufuehrung von rufsignalen zu fernmeldeleitungen, insbesondere in fernsprechvermittlungsanlagen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US13575680A 1980-03-31 1980-03-31
US135756 2002-04-30

Publications (3)

Publication Number Publication Date
EP0037540A2 EP0037540A2 (de) 1981-10-14
EP0037540A3 EP0037540A3 (en) 1982-09-15
EP0037540B1 true EP0037540B1 (de) 1986-01-02

Family

ID=22469517

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EP81102363A Expired EP0037540B1 (de) 1980-03-31 1981-03-28 Verfahren und Schaltungsanordnung zur Zuführung von Rufsignalen zu Fernmeldeleitungen, insbesondere in Fernsprechvermittlungsanlagen

Country Status (11)

Country Link
EP (1) EP0037540B1 (enrdf_load_stackoverflow)
JP (1) JPS56152361A (enrdf_load_stackoverflow)
AT (1) ATE17294T1 (enrdf_load_stackoverflow)
AU (1) AU541648B2 (enrdf_load_stackoverflow)
BE (1) BE888193A (enrdf_load_stackoverflow)
BR (1) BR8101844A (enrdf_load_stackoverflow)
CA (1) CA1172737A (enrdf_load_stackoverflow)
DE (1) DE3173346D1 (enrdf_load_stackoverflow)
ES (1) ES500922A0 (enrdf_load_stackoverflow)
MX (1) MX150197A (enrdf_load_stackoverflow)
NO (1) NO155598C (enrdf_load_stackoverflow)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2128449B (en) * 1982-10-08 1985-12-11 Standard Telephones Cables Ltd Tone generation circuit
US4656659A (en) * 1985-07-18 1987-04-07 Itt Corporation Programmable ring signal generator

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2129281A5 (enrdf_load_stackoverflow) * 1971-03-11 1972-10-27 Ibm France
US4097694A (en) * 1975-07-09 1978-06-27 Toa Electric Company, Ltd. Time-division telephone system embodying trunks having demodulating-adder circuits
JPS53124008A (en) * 1977-04-06 1978-10-30 Oki Electric Ind Co Ltd Call signal transmission system

Also Published As

Publication number Publication date
NO155598B (no) 1987-01-12
NO155598C (no) 1987-04-22
MX150197A (es) 1984-03-29
NO811094L (no) 1981-10-01
JPS56152361A (en) 1981-11-25
CA1172737A (en) 1984-08-14
ATE17294T1 (de) 1986-01-15
JPH0342534B2 (enrdf_load_stackoverflow) 1991-06-27
EP0037540A2 (de) 1981-10-14
ES8206125A1 (es) 1982-08-16
BE888193A (nl) 1981-09-30
EP0037540A3 (en) 1982-09-15
ES500922A0 (es) 1982-08-16
DE3173346D1 (en) 1986-02-13
AU6876581A (en) 1981-10-08
BR8101844A (pt) 1981-10-06
AU541648B2 (en) 1985-01-17

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